When you receive these events, the structure members are set as follows.

The type member is set to the event type constant name that uniquely identifies
it. For example, when the X server reports a GraphicsExpose event to a
client application, it sends an XGraphicsExposeEvent structure with the
type member set to GraphicsExpose. The display member is set to a pointer
to the display the event was read on. The send_event member is set to True
if the event came from a SendEvent protocol request. The serial member
is set from the serial number reported in the protocol but expanded from
the 16-bit least-significant bits to a full 32-bit value. The window member
is set to the window that is most useful to toolkit dispatchers.

The window
member is set to the window on which the EnterNotify or LeaveNotify
event was generated and is referred to as the event window. This is the
window used by the X server to report the event, and is relative to the
root window on which the event occurred. The root member is set to the
root window of the screen on which the event occurred.

For a LeaveNotify
event, if a child of the event window contains the initial position of
the pointer, the subwindow component is set to that child. Otherwise, the
X server sets the subwindow member to None. For an EnterNotify event,
if a child of the event window contains the final pointer position, the
subwindow component is set to that child or None.

The time member is set
to the time when the event was generated and is expressed in milliseconds.
The x and y members are set to the coordinates of the pointer position
in the event window. This position is always the pointer's final position,
not its initial position. If the event window is on the same screen as the
root window, x and y are the pointer coordinates relative to the event
window's origin. Otherwise, x and y are set to zero. The x_root and y_root
members are set to the pointer's coordinates relative to the root window's
origin at the time of the event.

The same_screen member is set to indicate
whether the event window is on the same screen as the root window and can
be either True or False. If True, the event and root windows are on
the same screen. If False, the event and root windows are not on the same
screen.

The focus member is set to indicate whether the event window is
the focus window or an inferior of the focus window. The X server can set
this member to either True or False. If True, the event window is
the focus window or an inferior of the focus window. If False, the event
window is not the focus window or an inferior of the focus window.

The state
member is set to indicate the state of the pointer buttons and modifier
keys just prior to the event. The X server can set this member to the bitwise
inclusive OR of one or more of the button or modifier key masks: Button1Mask,
Button2Mask, Button3Mask, Button4Mask, Button5Mask, ShiftMask,
LockMask, ControlMask, Mod1Mask, Mod2Mask, Mod3Mask, Mod4Mask,
Mod5Mask.

The mode member is set to indicate whether the events are
normal events, pseudo-motion events when a grab activates, or pseudo-motion
events when a grab deactivates. The X server can set this member to NotifyNormal,
NotifyGrab, or NotifyUngrab.

The detail member is set to indicate
the notify detail and can be NotifyAncestor, NotifyVirtual, NotifyInferior,
NotifyNonlinear, or NotifyNonlinearVirtual.